Metal-coated, ordered void piezoelectric ceramic material

Abstract

An ordered void piezoelectric ceramic material (e.g. lead zirconate titan (PZT)) has its inner void surfaces coated with a thin flexible layer of a metal (e.g. silver) by a process which includes the following steps. First a quantity of an ordered void piezoelectric ceramic material is obtained. Next, the ordered void piezoelectric ceramic material is impregnated with a solution containing a metal, such that inner surfaces of the voids of the ceramic material are wetted with the impregnating solution. Then, excess impregnating solution is removed from the external edges of the piezoelectric ceramic material, leaving the inner surfaces of the voids wetted with impregnating solution. Then, the void-wetted piezoelectric ceramic material is fired to bring about formation of a thin flexible metal coating on the inner surfaces of the voids of the piezoelectric ceramic material.

What is claimed is: 
     
       1. A piezoelectric ceramic material, comprising: an ordered void piezoelectric ceramic material, and a thin coating of an electrically conductive metal, having a thickness of 0.05-4 microns, deposited on inner surfaces of the voids of said ordered void piezoelectric ceramic material and not filling the voids. 
     
     
       2. The material described in claim 1 wherein said metal coating includes silver metal. 
     
     
       3. A method for producing a composite ordered void piezoelectric ceramic material, comprising the steps of: obtaining a quantity of ordered void piezoelectric ceramic material,   impregnating the ordered void piezoelectric ceramic material with an organometallic solution containing an electrically conductive metal, said impregnating solution having a viscosity and surface tension sufficiently low that said impregnation wets inner surfaces of voids of the ceramic material with the impregnating solution,   removing excess impregnating solution from the outside of the ceramic material leaving the inner surfaces of the voids wetted with impregnating solution, and   firing the wetted ceramic material to bring about formation of an electrically conductive, thin metal coating on the inner surfaces of the voids of the ceramic material.   
     
     
       4. The method described in claim 3 wherein the impregnating solution contains a form of silver. 
     
     
       5. The method described in claim 3 wherein the impregnating solution contains an organometallic form of silver. 
     
     
       6. The method described in claim 3 wherein the ordered void piezoelectric ceramic material is fired at a temperature in the range of 500-850 degrees Centigrade. 
     
     
       7. An ordered void piezoelectric ceramic material obtained by a process including the steps of: obtaining a quantity of ordered void piezoelectric ceramic material,   impregnating the ordered void piezoelectric ceramic material with an organometallic solution containing an electrically conductive metal, said impregnating solution having a viscosity and surface tension sufficiently low that said impregnation wets inner surfaces of voids of the ceramic material with the impregnating solution,   removing excess impregnating solution from the external edges of the ordered void piezoelectric ceramic material leaving the inner surfaces of the ordered void piezoelectric ceramic material wetted with impregnating solution, and   firing the wetted ordered void piezoelectric ceramic material to bring about formation of an electrically conductive thin metal coating, having a thickness of 0.05-4 microns, on the inner surfaces of the ordered void piezoelectric ceramic material.   
     
     
       8. A lead zirconate titanate (PZT) piezoelectric ceramic material, comprising: an ordered void lead zirconate titanate (PZT) ceramic material, and   a thin coating of an electrically conductive metal, having of thickness of 0.05-4 microns, deposited on inner surfaces of the PZT material.   
     
     
       9. The material described in claim 8 wherein said metal coating includes a metal selected from the group consisting of silver, gold, platinum, copper, nickel, and palladium and mixtures thereof. 
     
     
       10. A method for producing a composite lead zirconate titanate (PZT) ceramic material, comprising the steps of: obtaining a quantity of ordered void PZT material,   impregnating the ordered void PZT material with an organometallic solution containing an electrically conductive metal, said impregnating solution having a viscosity and surface tension sufficiently low that said impregnation wets inner surfaces of the voids of the PZT material with the impregnating solution,   removing excess impregnating solution from the external edges of the PZT material leaving the inner surfaces of the ordered void PZT material wetted with impregnating solution, and   firing the PZT material to bring about formation of an electrically conductive metal coating, having a thickness of 0.05-4 microns, on the inner surfaces of the ordered void PZT material.   
     
     
       11. The method described in claim 10 wherein the impregnating solution contains a form of silver. 
     
     
       12. The method described in claim 10 wherein the PZT material is fired at a temperature in the range of 500-850 degrees Centigrade. 
     
     
       13. A lead zirconate titanate (PZT) piezoelectric ceramic material obtained by a process including the steps of: obtaining a quantity of ordered void PZT material,   impregnating the ordered void PZT material with an organometallic solution containing an electrically conductive metal, said impregnating solution having a viscosity and surface tension sufficiently low that said impregnation wets inner surfaces of the voids of the PZT material with the impregnating solution,   removing excess impregnating solution from the PZT material leaving the inner surfaces of the ordered void PZT material wetted with impregnating solution, and   firing the PZT material to bring about formation of an electrically conductive metal coating, having a thickness of 0.05-4 microns, on the inner surfaces of the ordered void PZT material.   
     
     
       14. A piezoelectric sensor/transmitter, comprising: a first electrode,   a quantity of an ordered void piezoelectric ceramic material in contact with said first electrode,   a thin coating of an electrically conductive metal, having a thickness of 0.05-4 microns, deposited on inner surfaces of the voids of said ordered void piezoelectric ceramic material and not filling the voids, and   a second electrode contacting said quantity of ordered void piezoelectric material, said ordered void piezoelectric material located between said first and second electrodes.   
     
     
       15. The material of claim 1, wherein said metal coating includes a metal selected from the group consisting of silver, gold, platinum, copper, nickel, and palladium and mixtures thereof. 
     
     
       16. The method of claim 3, wherein said electrically conductive metal includes a metal selected from the group consisting of silver, gold, platinum, copper, nickel, and palladium and mixtures thereof. 
     
     
       17. The material of claim 7, wherein said metal coating includes a metal selected from the group consisting of silver, gold, platinum, copper, nickel, and palladium and mixtures thereof. 
     
     
       18. The material of claim 8, wherein said metal coating includes a metal selected from the group consisting of silver, gold, platinum, copper, nickel, and palladium and mixtures thereof. 
     
     
       19. The method of claim 10, wherein said electrically conductive metal includes a metal selected from the group consisting of silver, gold, platinum, copper, nickel, and palladium and mixtures thereof. 
     
     
       20. The material of claim 13, wherein said metal coating includes a metal selected from the group consisting of silver, gold, platinum, copper, nickel, and palladium and mixtures thereof. 
     
     
       21. The sensor/transmitter of claim 14, wherein said metal coating includes a metal selected from the group consisting of silver, gold, platinum, copper, nickel, and palladium and mixtures thereof.